Naphtha cracking has allowed large-scale production of the distilled fraction composed primarily of C4 compounds (the distilled fraction will be referred to as “C4 fraction”, hereinafter.): The C4 fraction has become readily available on industrial scale. Although the C4 fraction contains butenes and 1,3-butadiene which are useful to industrial raw materials, it also contains butynes, the compounds that, when subjected to later telomerization and other chemical processes, will not only form explosive materials, but also cause to decrease the activity of catalysts used for these reactions.
Thus, several approaches have been proposed to remove butynes from the C4 fraction. These techniques involve selectively hydrogenating butynes to convert them into olefins, which are then separated by fractional distillation and purified (See, for example, Patent Documents 1 and 2).
[Patent Document 1] U.S. Pat. No. 6,225,515
[Patent Document 2] Japanese Translation of PCT International Application No. 2001-500522